Evaluation of renal function change during first-line tyrosine kinase inhibitor therapy for metastatic renal cell carcinoma

BACKGROUND: The change in renal function induced by first-line tyrosine kinase inhibitor therapy for metastatic renal cell carcinoma remains unclear. METHODS: One hundred and thirty-four patients were evaluated. Sunitinib (SU) and sorafenib (SO) were administered to 91 (67.9%) and 43 (32.1%) patients, respectively. The change in estimated glomerular filtration rate (ΔeGFR) was calculated as [(eGFR at each time point – pre-treatment eGFR)/pre-treatment eGFR] × 100. ΔeGFR was compared between SU- and SO users using a mixed-effects model for repeated measures data with two or greater. Additionally, predictors for ΔeGFR ≤ −10% at 6 months after therapy initiation were evaluated using multivariate logistic regression analysis. RESULTS: Throughout the 24 months after therapy initiation, ΔeGFR was negatively greater in SU users, compared with that in SO users (P < 0.0001). In SU users, renal dysfunction was observed regardless of pre-treatment chronic kidney disease (CKD) status, whereas the magnitude of renal dysfunction was milder in SO users. In SO users without pre-treatment CKD, renal function did not significantly deteriorate. Moreover, ΔeGFR ≤ −10% was more frequently observed in SU users after 3 months (P = 0.0121) and 6 months (P = 0.0009). Finally, SU usage was an independent predictor for ΔeGFR ≤ −10% at 6 months (odds ratio 8.87, P = 0.0053), along with pre-treatment hypertension (odds ratio 4.69, P = 00072). CONCLUSIONS: Deterioration of renal function was stronger with SU than SO. During SU therapy, renal function should be monitored and pre-treatment kidney function should be taken into consideration for therapy selection.